A water jet injection device suitable for use in a dispenser is shown, for example, in German Offenlegungsschrift No. 32 34 957.2. This device is provided with connections for conduits which, on the one hand, are connected to the storage vessel containing either the fruit syrup or the concentrate and, on the other hand, communicate with a pressurized source of fresh water. The prior known arrangement is difficult and time-consuming to manufacture and assemble and occupies a lot of space. Moreover, the comparatively long connecting conduits are not only disturbing since only little space is available in a dispenser of such type, and have also proved to be complicated to clean or replace the conduits when one wishes to change from one mixing product to another one.